JPH1177789A - Molding method using thermoplastic elastomer composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the adherend to a die part to enhance productivity by adding a metal salt of fatty acid when a thermoplastic elastomer compsn. containing a partially or perfectly crosslinked rubber component is subjected to extrusion molding. SOLUTION: A thermoplastic elastomer compsn. containing a partially or perfectly crosslinked rubber component is used to perform molding. This thermoplastic elastomer compsn. is concretely obtained by dynamically heat-treating a blend material containing an olefinic resin, olefinic rubber and, if necessary, a softening agent in the presence of org. peroxide. At the time of molding by using the thermoplastic elastomer compsn., metal salt of fatty acid is added immediately before molding. As the metal salt of fatty acid, a metal salt of Li, Pb, Na, Al, Zn or the like of fatty acid such as lauric acid, myristic acid, palmitic acid or the like is used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to extrusion molding of a thermoplastic elastomer composition containing a partially or completely crosslinked rubber component, and more particularly, to an adhesion (crosslinked product) to a die portion generated during the molding. , Decomposed products and low molecular weight products).

[0002]

2. Description of the Related Art Conventionally, gaskets for building materials, automobile parts,
Vulcanized rubber has been frequently used for home electric appliances and the like. But,
If it is a vulcanized rubber, there are problems that the process is complicated, the cycle is long, and the moldability is poor. In addition, soft plastics such as soft vinyl chloride resin, ethylene vinyl acetate copolymer and low-density polyethylene have good moldability and high flexibility, but are inferior in heat resistance and rebound resilience, etc. It is not enough as a substitute. Therefore, in recent years, thermoplastic elastomer compositions containing partially or completely crosslinked rubber components have excellent compression set properties, heat resistance, rubber elasticity, and have the same moldability as thermoplastic resins. , Has become widely used.

[0003]

However, when extrusion molding is performed using the thermoplastic elastomer composition containing the at least partially crosslinked rubber component, deposits may be generated on the die portion of the extruder, It is necessary to frequently remove the deposits, and the productivity may be impaired. The present invention has been made in order to solve the above-mentioned problem, and provides a method for reducing the amount of deposits on a die portion when extruding a thermoplastic elastomer composition containing a partially or completely crosslinked rubber component. Is what you do.

[0004]

Means for Solving the Problems As a result of intensive studies to solve the above problems, when a thermoplastic elastomer composition containing a partially or completely crosslinked rubber component is extruded, a metal salt of a fatty acid is removed. The present inventors have found that the addition and extrusion molding meet the above-mentioned object, and have reached the present invention. That is, in the method for molding a thermoplastic elastomer composition of the present invention, in the extrusion molding of a thermoplastic elastomer composition containing a partially or completely crosslinked rubber component, the thermoplastic elastomer composition is formed immediately before the extrusion molding. And a metal salt of a fatty acid. At this time, the metal salt of the fatty acid can be added to the thermoplastic elastomer composition as a master batch in which the metal salt of the fatty acid is contained in a polyolefin resin or a thermoplastic elastomer. In addition, as the metal salt of the fatty acid, Li of a saturated fatty acid having 4 to 30 carbon atoms is used.
Salts, especially Li stearate, are preferred. Further, as the rubber component, an olefin rubber is preferable. Or, as the thermoplastic elastomer composition, styrene-butadiene rubber, polyisobutylene rubber, styrene-butadiene-styrene block copolymer, and hydrogenated products thereof,
A styrene-isoprene-styrene block copolymer and a hydrogenated product thereof, a styrene-isoprene-butadiene-styrene block copolymer, and one or more rubber components selected from the group consisting of the hydrogenated product thereof, and polypropylene. Those having are preferred.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. The present invention relates to a method for molding using a thermoplastic elastomer composition containing a partially or completely crosslinked rubber component. The thermoplastic elastomer composition containing a partially or completely crosslinked rubber component is a thermoplastic elastomer composition that can be produced by a conventionally known method. Specifically, for example, an olefin resin and an olefin rubber are required. It is obtained by dynamically heat-treating a blend containing a softener in the presence of an organic peroxide. A method for dynamically crosslinking in the presence of these organic peroxides is described, for example, in JP-B-53-34210.
JP-A-53-149241, JP-A-5-149241,
197544 and the like. Olefin resins include ethylene and propylene, butene-1,
Examples thereof include α-olefin homopolymers such as 4-methylpentene-1 and copolymers thereof. Among them, propylene resins, for example, isotactic polypropylene, random or block copolymers of propylene with α-olefins such as ethylene or butene-1, hexene-1, etc. are particularly preferred. Examples of the olefin rubber include an ethylene-α-olefin copolymer rubber and an ethylene-α-olefin-nonconjugated diene copolymer rubber. Further, a rubber softener such as process oil may be added as necessary.

Further, as the rubber component, a rubber other than the olefin rubber can be used alone or in combination with the olefin rubber. As such a rubber component, for example, styrene-butadiene rubber (SB
R), nitrile rubber (NBR), butyl rubber (IIR)
Rubber, polyisobutylene rubber, styrene-butadiene-styrene block copolymer (SBS) and its hydrogenated product (SEBS), styrene-isoprene-
Styrene block copolymer (SIS) and its hydrogenated product (SEPS), styrene-isoprene-butadiene-styrene block copolymer and its hydrogenated product (S
EEPS) and the like.

A thermoplastic elastomer composition containing a completely crosslinked rubber component can be obtained by kneading a mixture of an olefin copolymer rubber, a polyolefin resin and a curing agent at a vulcanization temperature until vulcanization is completed. can get. The method for producing the thermoplastic elastomer composition containing the completely crosslinked rubber component is described in, for example,
No. 5,184,448 and Japanese Patent Publication No. 58-46138. In the thermoplastic elastomer composition used in the present invention, if necessary, an antioxidant, a weather resistance stabilizer, an antistatic agent, a lubricant, an antiblocking agent, an antifogging agent,
Additives such as an antifungal agent, a flame retardant, and a pigment can be blended.

[0008] The present invention is characterized in that a metal salt of a fatty acid is added immediately before molding when molding using the above-mentioned thermoplastic elastomer composition. The metal salt of the fatty acid used in the present invention, lauric acid,
Li, Pb, Na, K, Ca, Mg, B of fatty acids such as myristic acid, palmitic acid, stearic acid, and behenic acid
Salts of metals such as a, Al, Zn and the like can be mentioned. Among them, a salt of a saturated fatty acid having 4 to 30 carbon atoms is preferable. Also, L
i-salts are preferred, and Li stearate, which is particularly effective when added in small amounts, is most preferred.

The amount of addition is appropriately determined according to the thermoplastic elastomer composition used, but is generally 0.1 to 3 parts by weight based on 100 parts by weight of the thermoplastic elastomer composition. If the amount is less than 0.1 part by weight, the effect cannot be obtained. If the amount exceeds 3 parts by weight, the surface of the molded article may be whitened.
More preferably, the amount is 0.3 to 2 parts by weight.

In the present invention, the addition of the fatty acid metal salt immediately before molding means that the fatty acid metal salt is not added simultaneously with the preparation of the thermoplastic elastomer composition. It may be added as a post-process to the composition, and in practice, some time may be interposed between the addition of the metal salt of the fatty acid and the molding. If the addition of the metal salt of the fatty acid is performed during the preparation of the thermoplastic elastomer composition, the effect of reducing the amount of deposits on the die of the extruder cannot be sufficiently exerted. As a method of adding a metal salt of a fatty acid to a thermoplastic elastomer composition containing a partially or completely crosslinked rubber component, the thermoplastic elastomer composition and the fatty acid are mixed using a mixer such as a Henschel mixer or a ribbon blender. And a method in which a thermoplastic elastomer composition and a metal salt of a fatty acid are supplied to the supply port of an extruder at a constant rate. Further, a method in which a metal salt of a fatty acid is previously kneaded at a high concentration with a polyolefin-based resin or a thermoplastic elastomer as a master batch and then added to a thermoplastic elastomer composition containing a partially or completely crosslinked rubber component can be adopted. However, even in this case, the same method as described above can be applied. The method of adding a fatty acid metal salt as a master batch is convenient because handling is easy. When a metal salt of a fatty acid is added as a master batch, the mixing ratio of the master batch containing the metal salt of a fatty acid to the thermoplastic elastomer composition to be added and mixed is preferably 40% by weight or less. This is because if the content is more than 40% by weight, the effect of reducing the amount of deposits decreases.

Further, as a method for producing a masterbatch in which a metal salt of a fatty acid is blended in a high concentration with a polyolefin resin or the thermoplastic elastomer, a predetermined amount of each component is measured by using a Banbury mixer, a single screw extruder, a twin screw extruder. And the like, and kneading with an ordinary kneading machine to form pellets.

The molding method of the present invention can be used for T-die (sheet, film) molding, profile extrusion molding, blow molding and the like. The fields of use of the thermoplastic elastomer molded product obtained by the present invention include home electric appliance parts (packings and hoses), interior and exterior parts of automobiles (skin materials such as doors and instrument panels), and building material parts.

[0013]

〔raw materials〕

Preparation of Partially Crosslinked Thermoplastic Elastomer Composition TPO-1: Propylene content 28 wt%, iodination 1
5. Ethylene-propylene-ethylidene norbornene copolymer rubber having a Mooney viscosity of ML _{1 + 4} (100 ° C.) 90
0% by weight, MFR 1g / 10min homopolypropylene 33% by weight, mineral oil rubber softener (Idemitsu Kosan “PW
380 ”), 17% by weight and 0.8 parts by weight of triallyl isocyanurate (TAIC) were kneaded with a Banbury mixer at 180 ° C. for 5 minutes in a nitrogen atmosphere, passed through a roll, and pelletized by a sheet cutter. Next, 100 parts by weight of the pellets were mixed with an organic peroxide (2,5).
-Dimethyl-2,5-di- (t-butylperoxy)-
Hexane: "Kayahexa AD" manufactured by Kayaku Akzo) was mixed in an amount of 0.4 part by weight with a Henschel mixer, and the pellets were heated at a temperature of 220 ° C using a twin screw extruder (KTX-30) in the same direction.
To obtain pellets of a partially crosslinked thermoplastic elastomer composition.

TPO-2: propylene content 28 wt
%, Iodination 15, Mooney viscosity ML _{1 + 4} (100 ° C) 9
0, ethylene-propylene-ethylidene norbornene copolymer rubber 45% by weight, MFR 1 g / 10 min homopolypropylene 20% by weight, mineral oil-based rubber softener (Idemitsu Kosan (PW380)) 35% by weight, triallylisocyan 0.8 part by weight of Nurate (TAIC) was kneaded with a Banbury mixer in a nitrogen atmosphere at 180 ° C. for 5 minutes, passed through a roll, and pelletized by a sheet cutter. Next, 100 parts by weight of the pellets were mixed with an organic peroxide (2,5-dimethyl-2,5-di- (t-butylperoxy) -hexane: "Kayahexa AD" manufactured by Kayaku Akzo).
4 parts by weight were mixed with a Henschel mixer, and the pellets were mixed with a co-axial twin screw extruder (KTX-30) at a temperature of 22 wt.
The mixture was melt-kneaded at 0 ° C. to obtain pellets of a partially crosslinked type thermoplastic elastomer composition.

Li master stearate (MB)
Preparation of -1) 95% by weight of the above TPO-1 and 5% by weight of Li stearate were mixed with a Henschel mixer, and the mixture was melted at 220 ° C. using a co-directional twin screw extruder (KTX-30). The mixture was kneaded to obtain a master pellet of Li stearate.

Examples 1 to 7 The thermoplastic composition elastomer compositions (TPO-1 and TPO-2) prepared above were mixed with the fatty acid metal salt (Li stearate) so as to have the compounding ratio shown in Table 1. , Zn stearate) or a master batch (MB-1) was mixed with a Henschel mixer, and the resulting mixture was mixed with a 20 mm φ single screw extruder equipped with a Garvey die described in ASTM D2230.
Extruded for 40 minutes (screw rotation speed: 40 rpm, die temperature: 190 ° C.). Thereafter, the attached matter attached to the die part was collected and its weight was measured. The obtained measured value was multiplied by 4 to calculate the amount of deposits per hour. [Comparative Examples 1 and 2] As shown in Table 2, the thermoplastic composition elastomer compositions (TPO-1, TPO-
Extrusion was carried out in the same manner as in Example 1 using 2), and the adhered matter adhered to the die portion was collected and its weight was measured.

Comparative Example 3 Propylene content 28 wt
%, Iodination 15, Mooney viscosity ML _{1 + 4} (100 ° C) 9
0 ethylene-propylene-ethylidene norbornene copolymer rubber 50% by weight, MFR 1 g / 10 min. Homopolypropylene 33% by weight, mineral oil rubber softener ("PW380" manufactured by Idemitsu Kosan) 17% by weight, Li stearate
With 0.3 parts by weight of triallyl isocyanurate (TA)
IC) was mixed at a temperature of 180 ° C. for 5 minutes in a nitrogen atmosphere with a Banbury mixer in a nitrogen atmosphere, and then passed through a roll to produce pellets by a sheet cutter. Next, to 100 parts by weight of the pellet, 0.4 part by weight of an organic peroxide (2,5-dimethyl-2,5-di- (t-butylperoxy) -hexane: "Kayahexa AD" manufactured by Kayaku Akzo) was added. The pellets were mixed by a Henschel mixer, and the pellets were melt-kneaded at a temperature of 220 ° C. using a co-directional twin screw extruder (KTX-30) to obtain pellets of a partially crosslinked thermoplastic elastomer composition. Extrusion molding was performed using the pellets in the same manner as in Example 1 described above, and the adhered matter adhered to the die portion was collected and its weight was measured.

[0018]

[Table 1]

[0019]

[Table 2]

From Table 1, it can be seen that according to the method of this embodiment, the amount of deposits can be reduced. However, in Comparative Examples 1 and 2 in which no metal salt of a fatty acid was added,
Large amounts of deposits were generated. In Comparative Example 3 in which Li stearate was added at the same time as the preparation of the thermoplastic elastomer composition, the effect of reducing the deposits was not so much exhibited. Examples 1 to 6 using Li stearate as a metal salt of a fatty acid were superior to Example 7 using Zn stearate.

[0021]

According to the present invention, deposits generated during extrusion molding of a thermoplastic elastomer composition containing a partially or completely crosslinked rubber component are reduced, and productivity is dramatically improved. .

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI B29K 105: 26

Claims (6)

[Claims] In the extrusion molding of a thermoplastic elastomer composition containing a partially or completely crosslinked rubber component, it is preferable to add a metal salt of a fatty acid to the thermoplastic elastomer composition immediately before the extrusion. A method for molding a thermoplastic elastomer composition. 2. The method according to claim 1, wherein the metal salt of the fatty acid is added to the thermoplastic elastomer composition as a master batch in which the metal salt of the fatty acid is contained in a polyolefin resin or a thermoplastic elastomer.
A method for molding the thermoplastic elastomer composition according to the above. 3. The method according to claim 2, wherein the metal salt of the fatty acid has 4 to 30 carbon atoms.
2. A Li salt of a saturated fatty acid according to claim 1.
Or the molding method of the thermoplastic elastomer composition according to 2. 4. The method of molding a thermoplastic elastomer composition according to claim 3, wherein the Li salt of the saturated fatty acid is Li stearate. 5. The method for molding a thermoplastic elastomer composition according to claim 1, wherein the rubber component is an olefin-based rubber. 6. The thermoplastic elastomer composition comprises styrene-butadiene rubber, polyisobutylene rubber, styrene-butadiene-styrene block copolymer, and a hydrogenated product thereof, styrene-isoprene-styrene block copolymer, and 2. The composition according to claim 1, comprising one or more rubber components selected from the group consisting of a hydrogenated product, a styrene-isoprene-butadiene-styrene block copolymer, and a hydrogenated product thereof, and polypropylene. 5. The method for molding a thermoplastic elastomer composition according to any one of items 1 to 4.